Carburetor throttle control



l. E. coFFEY 2,148,729

CARBURETOR THROTTLE CONTROL Feb. 28, I1939.

Filed June 24, 193'? 2 sheets-shewu 1 lNvENToR. ffl/N f, fa/:ffy

ATTORNEY.

Feb. 28, 1939.' v 15E. coFFl-:Y

I CABUR'TOR THROTTLE CONTROL 2 Sheets-Sheet 2,

Filed June 24, 1957 JNVENTOR Z@ XM f m m Penas, 193s I 2.148.129.caasnaa'roa rnnomn oon'raor.

n-ven E. ceney, sauna, Mo.. suine: te omer Carburetor Corporation, St.Louis, Mo.,` a oorporation of Delawarev Application June 2.4, mi, serialNo. 15am v'I'his invention relates to carburetors for automobile enginesand consists particularly i'n,

novel throttle control means therefor.

Modern automotive carburetors are usually si provided with means forincreasing the richness of mixture supplied when the associa engineV isbeing subjected to abnoneuy' heevy loads. Such. condition is ordinarilyaccompanied by substantial opening of the throttle valve and lrelatively low suction in the intake passages. 'Ihe additional richnessmay be obtained by means' for increasing the enective size of the mainmetering orifice or by a device for opening an auxiliary fuel supply tothe mixture conduit and v --lli the auxiliary enrichener may becontrolled manually with the throttle valve or -by means'of a suctionactuated mechanism. In the case of a manual enrichener such as athrottle-controlled stepped metering rod cooperating with the main 20metering orifice, the power step of the metering rod must necessarily bebrought into operative relationship with-'the metering orlnce wheneverthe throttle is opened to the predetermined de-` gree regardless of'therate of speed or the load 25 vapplied to the engine. v'I'he additionalrichness provided by the power step" at low speeds is es- `.sential forobtaining maximum power from the engine, but during acceleration andhigh speed operation, thisl extra richness .accounts for only" 30 slightif any essential.

'nie' average automobile driver rarely subjects improved perfomance andis not his engine to c'onditionarequiring maximum power `and,accordingly, seldom actually needs the 35 additional richness whichaccompanies full opening of the throttle valve. Such a. driver is ordi-.narily not suiliciently skilled to operate the throttle valve in themost economical manner. though it could be so operated withoutnoticeably af- 40 fecting the operation of his car. Consequently, whenhe desires rapid acceleration or increased power, lie depresses-histhrottle pedal ymuch more than is necessary and wastes fuel.

yAn oblect 'of the present invention is to\pro- 45 vide means forselectively limiting the degree to which the carburetor vthrottle valvemay bev opened.

.Another object is to provide manual means for varying the eifectlverelationship between the 50 throttle and its control pedal or lever.

Another object is to provide automatic means for limiting the degreetowhich thethrottle .valve may be opened when normal driving conditionsprevail while permitting greater or full 56 opening of the throttleunder other conditions.

hereafter appearing are Still another object is to provide means formaking operation of the throttle valve easier for city or other drivingwhen repeated variation of the throttle position is necessary.

'I'hese objects and other more detailed objects attained substantiallyby the devices illustrated in the accompanying Fig. '1 is a view. partlyin section.. showing parts of an internal combustion engine andcarburetor control mechanism therefor.

Fig. 2 is a' view of the mechanism taken on line 2--2 of-Flgure'l, theflooring being omitted.

Fig. 3 is a section taken substantially on line 3-3 of/Figure 2.v

Fig. 4 is a view similar to Figure 1, but showing a modification.

Fig.5 is a diagrammatic 4representation showing operative parts of acarburetor and another drawings, in which:

form of the invention.

Fig. 6 diagrammatically illustrates still another form.

Figures 1 and 4 show a portion of internal combustion engine I. of theusual automotive type, having exhaust manifold 2 and intake manifold 3merging in hot spot vconstruction 4 for applying exhaust, heat to theintake gases. Moimted'on the hot spot is a carburetor, generallyindicated at i, having a throttle valve 6' mounted near the ouuetporuonthereof.' As. show n in'Figure 5, the carburetor also icludesf adowndraft -mixture conduit at l, venturis 8, choke valve 9. and mainnozzle lli. Adjacent the mixture conduit is a constant level .chamber il.having thev usual float controlled inlet valve mechanism (not shown).

Fuel is supplied to main nomle It through metering orince member I2 andaccelerating fuel is supplied from pump Il. The en'ective size of`orince member I2 may be varied by movement of the stepped metering rodI4 carried by rock lever I5 manu'- ally controlled with thev throttlevalve through link I l and arm l1 rigid with the throttle shaft.

Accelerating pump Il is also manually controlled from the throttle.

Pivoted to` a bracket Il projecting from the flooring or frame adjacentthe drivers seat is a rock lever -Il connected at one end. with thethrottle arm Il by means ofa link 20. The opposite extremity of lever ilis provided with a slot 2i which slidably receives the bent over endportion 22 of'push rod -23 secured at its upper end to theusual throttlecontrol pedal 24, Rod 22 passes through an opening 2l in the flooring2C.'

A p intle 2l depending from a portion of floor- REISSUED4 DEG 3 1940 mgzsspaced'iaterauy from rock lever is pivo'tallyj'mlounts .a lever 26extending substantially ata rightangle to lever |9 and parallelingflooring 26. Lever 28 is yieldably held in position wishes to obtainmaximum economy which alccompanies restriction of the degree to whichthe throttle may be opened, lever 28 may be manually rotatedcounterclockwise, with reference to Fig. 2, so as to move push rod 23 tothe outer extremity of slot 2|. Such movement increases the leveragerelationship between the throttle valve and its control pedal, or,-inother words, varies the mechanical advantage of the throttle controlmechanism so that full movement'of pedal 24 produces only partialopening movement of the throttle valve. Obviously the maximum degree towhich the throttle may be opened by the pedal may be varied by merelymoving push rod 23 to different positions in slot 2|. With rod 23 at theouter end of slot 2|, the throttle valve can be opened only to theposition indicatedV in Fig. 5 with the larger orso-called economy stepof metering rod I4 still restricting metering orifice.

In Fig. 4 the throttle vcontrol mechanism is the same as that shown inthe previous form, and a modified form of mechanism for varying themechanical advantage between the throttle valve and its control pedal isshown. This mechanism comprises a suction actuated device shownconventionally at 33, in which a. diaphragm (not` shown) is normallyurged to the right by-a spring. The suction device is connected tointake manifold 3l by means of a tube 34 in winch is interposed a manualshutoff valve 35. Suction device 33 operates a rod 36 which is connectedby means of a pivoted lever 31 to a reach rod or link 33 having anaperture 39 loosely'receiving` throttle push rod 23. This rod is shownin solid lines at the outer end of slot 2l to which position it is movedwhen relatively high suctions prevail in the intake manifold. In thisposition of parts, the throttle valve is only partially opened, asindicated at 6a, when pedal 24 is fully depressed. 'Fig. 4 also shows indot and dash lines the throttlel push rod moved to the inner end of slot2|'to permit full operation of the throttle, such movement being eectedwhen lsuction in the intake manifold drops below a predetermined value.VValve 35 provides for manually cutting oii suction applied to suctiondevice 33, whereupon push rod 23 will be moved to and held in the'broken line position. The calibration of the suction device andconnections shown in Fig. 4k varies with difierent engines. Preferably,device 33 should move rod 23 from the solid line position in Fig. 4 to`the broken line position when the suction in the intake manifold dropsfrom a value corresponding to, say, eight to ten inches of mercury to avalue corresponding tofour to seven inches of mercury. Thus, when thesuction in the intake manifold exceeds the top suction limit mentioned,which condition prevails during most normal driving, the throttleconnections, will be adjusted for the most economical operation. In

case. however, the intake suction drops, as when the engine is subjectedto an abnormal load or the throttle is opened quickly. push rod 23 willbe automatically slid along slot 2| to permit a greater opening ot thethrottle valve. Such a movement of the push rod will also occur in casethe engine speed tends to become slower and the throttle pedal is heldstationary with the result that the throttle will be automaticallyopened and -additional power provided.

Figs. 5 and 6 illustrate diagrammatically hydraulic or pneumaticarrangements for operating the throttle valve. In Fig. 5, a valve 40controls the branched fluid connection between primary cylinder 4|,receiving piston 42 connected to throttle pedal 24 and secondarycylinders 43 and \44 having pistons 45 and 46 connected to throttle armI1 by balance lever 41 and link 48. Valve 40 has an operating handle 49easily accessible tc the driver of thev vehicle for connecting primary`tube 50 with either of the tubes 5| or 52. When cylinder 4| is openedto cylinder 43 by means or valve 49, full depression of pedal 24 fullyopens the throttle valve. In case valve 40 isset to connect the primarycylinder to cylinder 44,

which is larger than cylinder 43, full movement of the pedal operatesthe throttle valve only to the partially open position shown with theecon-g v omy step of the metering rod still in the metering orifice. asexplained above.

In Fig. 6, a suction device 53 somewhat similar to that in Fig. 4communicates through tube 54 with the fluid connection 55 connectinghydraulic cylinders 56 and 51. Piston 58 in cylinder 56 is connected topedal 24 and piston 59 in cylinder -51 is connected to throttle arm i1.

A spring loaded check valve 65 in tube 64 has a restricted centralaperture 56 whereby the valve impedes movement of the hydraulic fluidfrom the 'suction device into connection 55 but oiers substantially noresistance to passage ofv the fluid through tube 54 in the oppositedirection.

When a substantial drop occurs in the intake suction communicated todevice 53 through con#- duit 60, spring 6| moves diaphragm 62 upwardly.This movement forces a part of the fluid from the suction device intotube ,55 and cylinder 56 fully raising piston 59'and pedal 24. 'Ihisaction d oes not aiect the throttle since throttle spring 64 is strongerthan spring 63. When the suction device is thus discharged, so to speak,full depression of `pedal 24 operates the throttle since pedal piston 56is at the top end of its stroke,

and slightly opens the-vthrottle preparatory to restarting the engine.Such automatic reopening oi' the throttle occurs slowly due to therestriction at check 55.

When the intake suction is relatively high as is the c ase under mostnormal driving conditions, diaphragm 62 will be lowered against spring6|, drawing uid from connection 55 into the suction device. Thereafter,until the suction again drops, the throttle pedal will be only partiallyraised when the throttle isofully closed by its return 'spring andconsequently depression of the pedal from such position can onlypartially open the throttle.

carburetor having a metering rod. controlled manually with the throttlevalveand the adthe relationship between the throttle valve and the powerstep of the fuel metering rod. Where the invention is used with thesuction step-up type of carburetor, adjustment of the various mechanismswill depend on the suction condition in the intake or carburetor atwhich the suction step-up device is arranged to provide'the in` creasedrichness. Suction device Il should move rod 23 to the inner end of slot2| before the intake manifold suction drops suiiiciently to causefunctioning of the auxiliary enriching device.

An example of a i'orm of suction step-up device vis shown in aco-pending application of Leland Read, Serial No. 129,786, illed March9, 1937. e invention is adapted for application to all" types ofthrottle controlled, internal combustion engines.

An additional' advantage oi the invention results from the fact thatvarying the mechanical advantage of the throttle control mechanism notonly limits the extent to which the throttle valve l -may be opened" butalso makes opening of the 'valve against the throttle return spring (notshown) substantially easier. I'he invention con- .templated broadlyvarying the mechanical advantage of the throttle control mechanism,however eilected.

lvarious parts of the structures shown are not essential and these maybe modiiied as willv occur 'to those skilled in the art. The'exclusiveuse of all such modifications as come within the scope of theappendedclaims is contemplated.

I claim: i. In combination, acarburetor throttle valve element, amanualcontrol element therefor, and

mechanism for varying the operative 'relationship between said elementscomprising a pivoted lever having a recess, a link connecting one ofsaidelements with a portion of said lever spaced from said recess', and alink exte'nding from the other of said elements to said recess andmovable"4 therein to vary the leveragerelationship between saideiements.`

2. In combination, 'a carburetor throttle valve, a manual controlelement therefor, a pivoted lever having a slot. .a link connecting saidvalve with a portion of said lever spaced from said slot, a second -llnkconnecting said control element with said slot, and structure extendingfrom said second link and accessible with said control element formoving said second link in said slot to vary the operative relationshipbetween said control elementfand said valve. 3. The combination ofelements specied in claim 2 constructed and arranged so that fullmovement of said control element is capable of moving said throttlevalve only to a partially open position when lsaid second link is inapre-A determined position in said slot.

4. In combination, 'a carburetor throttle valve element, a controlelement therefor, a pivoted lever having a recess, a link connectingone, of

" maf elements and .portion of nia lever am connecting said elements,and means including a member responsive to suction in said intakestructure for varying the mechanical advantage of said mechanism to varythe operative relationship between said elements.

6. The combination of elements specified in claim 4 in which saidmechanism and said means are constructed and arranged so that whenrelatively high suctions prevail in said intake structure, full movementof said control element produces only partial opening movement of saidthrottle valve element.

' 7. In combination, a carburetor throttle valve, iluid pressuremechanism including a manual control for operating said valve, and meansfor varying the effective relationship between said control and saidvalve, said mechanism includingseparate devices operable to providediii'erentl-operative relationships kbetween said valve and saidcontrol. said means'rfunctioning to render said devices selectivelyoperative.

8. In combination, afcarburetor throttle valve,

a manual control therefor, a primaryl'iluid pressure device connected tosaid control, a pair of secondary iiuid pressure devices connected tosaid valve', and constructed and arranged to variably translate iiuidpressures transmitted from said primary device, uid connections betweensaid devices. and valve means for selectively connecting primary deviceto said secondary devices.

9. In combination, a carburetor throttle valve,

a manual 'control therefor. a duid pressure optio'n conditions in theintake of an associated engine.

l0. Structure as speciiled in claim 9 in which said suction operateddevice functions to vary the effective sise of said connection accordingto suction conditionsin the intake of an associated engine.

1i. In combination with an internal combustion engine, a carburetorthrottle valve. a manual control therefor, and means selectivelyresponsive to operative conditions in the engine f for varying theeiiective relationship between said valve and said control. said meansbeing constructed and arrangedtopartiaiiyopensaid valve when the engineis inoperative.

. Xmvm n com?.

